Improvement in valve-gear for steam-engin es



3 Sheets-Sheet.1 G. W. COPELAND.

Valve-Gear for Steam-Engines. 1 No. 222,459. Patented Dec. 9, 1879.

725 $71,635 es; I 71 W6 3 NJEIERS. PHOTO LITHOGRAPNER. WASHINGTON. D. C.

3 Sheets-Sheet 3.

c.,w. COPELAND. Valve-Gear for Steam-Engines. No. 222,459. Patented Dec.9, I879.

".FETERS. PHQTU-UTHOGRAPHER, WASHINGTON. D, C.

UNITED STATES PATENT FFICE.

CHARLES W. COPELAND, OF NEW YORK, N. Y.

IMPROVE MENT IN VALVE-GEAR FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 222,459, dated December9, 1879 application filed October 3, 1879.

To all whom it may concern:

Be it known that I, CHARLES W. COPELAND, of New York, in the county ofNew York, and State of New York, have invented a new and usefulImprovement in Steam Engines, of which the following is a specification,reference being bad to the accompanying drawlngs.

The said invention relates to the valve-gear in general use on theengines of the steamboats on the Ohio and Mississippi and other rivers,commonly known as the lever valvegear, as applied to the operating ofpuppetvalves in. theclass of engines referred to.

In these engines, as is well known, the valvegear is actuated by a camof peculiar form, the proportions of which determine the point ofcutting off and the extent to which the steam is worked expansively,the. point of cutting off not being adjustable after having thus beendetermined by the form and proportions of the cam. From certainpractical difficulties and objections such cams are rarely constructedto cut off at a shorter point than onehalf stroke, the more commonconstruction being such as to cut off at about five-eighths the strokeof the piston.

The object of my improvement is, that while the general features of thiscam andlever valvegear are retained, to make'such additions that mum maybe determined by the additional adjust-able apparatus which I apply, sothat the cut-off having at its maximum point say five-eighths of thestroke of the piston-the point of cut-01f may be adjustable to any pointwithin one-half of the stroke of the piston while the engine is inoperation, and without in any manner altering or affecting the operationof the cam and lever valve-gear now in common use on the class of engines referred to.

My invention consists in the application of a trip-motion to thesteam-valves, by which they will be reseated earlier in the stroke thanif reseated by the action of the cam or eccentric only.

The fall of the valve to the seat is regulated by what is known as adash-pot, and which is now in common use with other styles ofvalve-gear. The time of tripping the valve 1S determined by the positionof an inclined plane or cam, adjustable by the hand of the engineer,which cam acts to break theconnection of the actuating mechanism betweenthe cam or eccentric and the valve, thus permitting the valve to bereseated or closed independently of the actuating movement.

To enable others skilled in the arts to which my improvement appertainsto make and use my invention, I will proceed to describe itsconstruction and operation by reference to the accompanying drawings, inwhich- Figure l is a central vertical longitudina section of a deviceembodying the elements of the invention. Fig. 2 is a transverse sectionof same through the lines as :t' of Fig.1. Fig. 3 is an end view of theinvention. Fig. 4: is a top view of same. Fig. 5 shows an engine havingmyimproved valve'gear attached, and Fig. 6 is a top view of same.

The steam-cylinder A, with its valves, the

'side pipes, B, the steam-chests D, the oscillatory valve-levers E, andthe wipers or toes F; are all of usual construction and of the formcommonly used.

The valve-stem 0, instead of bearing directly upon the lever E or upon acam, as heretofore, rests upon the front portion of a sliding catch orpiece, I), which is secured so as to be capable of horizontal movementupon the lever E, between the journals d. The rear portion of theslide 1) is formed with two corresponding slots, f, one on each side, inthe outer ends of which are mounted the friction-wheels 9', hereinaftermentioned. The valve-stem a is constructed with a vertical slot, h,through which the leverE passes, and which is supplied with the featheri, which rests upon the front edge of the slide 11, and constitutes thebearing-surface of. the stem a. 1n rear of the valve-stem a is secured,in any convenient manner, the slide 70, the lower end of which is forkedand provided with cams m. When in position the forked ends of the slide70 pass downward through the slots f in close relation to thefriction-wheels g: The slide 1) is kept in place by the spring 6 whennot forced back by the cams m; but when thus forced back the slidingpiece or catch passes from under the feather i of the valve-stem, andallows the valve to drop to its seat. The fall of the valves to theirseats is controlled by the dash-pots F F, which are filled with anysuitable fluid for the purpose. \Vhen the lever E is raised the catch bpasses upward over the forked end of the slide it until thefriction-wheels g meet the inclined planes or cams m, which force thesaid wheel and sliding catch b outward, drawing the catch from under thefeather 1', and permitting the valves to be reseated.

The inclined planes or cams m may be adjusted at different heights, andthus the point at which the catch 1) is to withdraw from under thefeatherz' and allow the valves to drop may be controlled at will.

For the purpose of readily changing the point of cut-ofi', the slide khas cast upon one of its faces a rack, 12, in which works a smallpinion, p, which pinion is fastened on the small rod or shaft 1". ()nthis shaft is also fastened a hand-lever, o, by moving which the pinionis moved in either direction, and the slide 7:, with its cams m, raisedor lowered, and thus determining the point at which the sliding piece bshall be pushed or drawn from under the feather i of the valve-stem andallow the valve to drop; or the slide it may be thrown out of actionentirely, and thus permit the steam-valves to be worked in the usualmanner, and the time of seating of the valve determined by the actuatingcam or eccentric.

To secure the prompt reseatin g of the valves when the sliding piece orcatch 11 is withdrawn, I apply the spiral spring t around the upper endof the stem, and bearing upon a shoulder on the stem or on a collar orpin to start the valve back to its seat.

For the purpose of adjusting the spring I employ the adjusting-screw 'u,by working which more or less pressure may be put on the spring tosecure its prompt and proper action.

Although in the arrangement shown on the drawings there are twodash-pots shown to each valve, this is not a necessity, as a singledash-pot may he used either at the upper or lower end of the valvestem,and it will sometimes be more convenient to do so.

When used at the upper end of the valvestem, the stem can be prolongedthrough and above the adjusting-screw u and the dashpot set above thescrew or the dash-pot may be set below the screw and the valve-stemprolonged through the upper end ofthe dash-pot, and the adjusting-screwlocated above the dash-pot. 0n the other hand, if the dash-pot be placedbelow the valves, the dash-pot is attached to the lower end of thevalvechest and the lowerend of the valve-stem prolonged into thedash-pot, the adjustingscrew a, and the springs for returning the valvesto their seats being located as shown in the drawings.

Of course many of the parts here described may be omitted, and stillhave an adjustable and operating cut-0h gear. For instance, the racksand pinions, with their shaft for adj usting the slide it, may beomitted and the slide adjusted by hand and fastened; the dash-pots maybe omitted and the valves permitted to fall to their seats unresisted orretarded by friction or other means; the adjusting-screws and springsfor securing a prompt return of the valves to their seats may beomitted, and other means, such as the application of weights, used forthe purpose; or there may be no such means used, the valves to work sofreely as to be returned by gravity alone. Further, the slide k may beomitted and the sliding pieces or catches b adjusted by hand andfastened, or the feather be omitted and a roller or some othersubstitute applied; but with any or all these omissions or substitutionsthe result will still be an adjustable cut-off arrangement, incombination with the ordinary lever valvegear, as has been described,and shown in the accompanying drawings.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. In valve-gear for engines in which the lever is actuated by a rockingcam or lever, a sliding catch operated by a sliding cam, which may beadjusted at difl'erent relations to the said sliding catch, and thusgovern the point at which the said catch shall be withdrawn from beneatha feather connected with the valve-stem, whereby the said stem isallowed to drop and cut off the steam, substantially as set forth.

2. In valve-gear for engines, the combination of the lever E, slidingpiece or catch b, spring 0, feather i, and slide is, having cams m,substantially as specified. 3. In valve-gear for engines, the combinetion of the lever E, sliding catch 1), spring', feather i, and slide k,provided with the cams m, rack 11, and pinion 10, substantially asspecilied.

4. In combination with the lever E, actuated by a rocking cam or lever,the sliding catch or piece I), having a spring-tension, the valvestemat, having thespring t and adjustingscrew 14, the feather t, the slidelo, having cams m, rack n, and pinion 12, substantially as set forth.

In testimony that I claim the foregoing i mprovement in steam engines,as above described, I have hereunto set my hand this 27th day ofSeptember, 1879.

CHAS. W. COPELAND.

Witnesses:

WM. BRO. SMITH, ROWLAND Cox.

